Field of the Invention
This invention relates to a control apparatus for an automatic transmission, more specifically to a control apparatus for an automatic transmission that can reliably detect or determine malfunction of a torque converter lock-up clutch and implement appropriate fail-safe control when malfunction is determined.
Description of Related Art
A technique for detecting or determining lock-up clutch malfunction in an automatic transmission equipped with a torque converter having a lock-up clutch, more precisely for detecting or determining abnormal sticking of the lock-up clutch in the engaged position, can be found, for example, in Patent Reference 1 (International Publication WO 2014/017239). The teaching of Patent Reference 1 is to detect or determine engage-position sticking of a lock-up clutch based on a torque converter slip ratio of transmission input rotational speed relative to prime mover (e.g., internal combustion engine) output rotational speed, and hydraulic oil temperature.